Supernovae evidence for dark energy. Hubble Space Telescope images of five distant supernovae that were observed as part of a study that confirmed that dark energy existed in the early universe. Dark energy is a repulsive force that in the early universe overcame the initial slowing down of the universe's expansion, and, from 5-6 billion years ago, has caused the universe to expand at an increasing rate. The images in the top row show distant galaxies containing a supernova (seen as a bright dot), and the images in the bottom row show the galaxies before or after the supernova. These events in the early universe can be observed because the light from them has taken billions of years to reach Earth. These results were published in 2006.